Interbody spacer

ABSTRACT

An interbody spacer is provided including a body portion defining a longitudinal axis. The body portion includes a distal end portion, a proximal end portion, opposed side surfaces that extend between the distal and proximal end portions, and top and bottom surfaces configured and adapted to engage vertebral bodies. The interbody spacer includes first orifices defined through the top surface. The first orifices include orifices having first and second cross-sectional configurations and the first orifices are arranged in rows extending along the longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S.Provisional Patent Application Ser. No. 62/108,197, filed on Jan. 27,2015, U.S. Provisional Patent Application Ser. No. 62/196,371, filed onJul. 24, 2015, and U.S. Provisional Patent Application Ser. No.62/240,662, filed Oct. 13, 2015. The entire contents of each of theseprior applications are hereby incorporated by reference herein.

BACKGROUND

Technical Field

The present disclosure relates to an apparatus for treating spinalconditions, and more particularly, to an interbody spacer and a methodof use therefor.

Background of Related Art

The human spinal column is a highly complex structure. It includestwenty-four discrete bones, known as vertebrae, coupled sequentially toone another to house and protect critical elements of the nervoussystem. The vertebrae interlock with one another to form a spinalcolumn. Each vertebra has a cylindrical bony body (vertebral body), twopedicles extending from the vertebral body, a lamina extending from thepedicles, two wing-like projections extending from the pedicles, aspinous process extending from the lamina, a pars interarticularis, twosuperior facets extending from the pedicles, and two inferior facetsextending from the lamina.

The vertebrae are separated and cushioned by thin pads of tough,resilient fiber known as inter-vertebral discs. Inter-vertebral discsprovide flexibility to the spine and act as shock absorbers duringactivity. A small opening (foramen) located between each vertebra allowspassage of nerves. When the vertebrae are properly aligned, the nervespass through without a problem. However, when the vertebrae aremisaligned or a constriction is formed in the spinal canal, the nervesget compressed and may cause back pain, leg pain, or other neurologicaldisorders.

For many reasons, such as aging and trauma, the intervertebral discs canbegin to deteriorate and weaken, potentially resulting in chronic pain,degenerative disc disease, or even tearing of the disc. Ultimately, thedisc may deteriorate or weaken to the point of tearing and herniation,in which the inner portions of the disc protrude through the tear. Aherniated disc may press against, or pinch, the spinal nerves, therebycausing radiating pain, numbness, tingling, and/or diminished strengthor range of motion.

Many treatments are available to remedy these conditions, includingsurgical procedures in which one or more damaged intervertebral discsare removed and replaced with a prosthetic. After a partial or completediscectomy, the normally occupied space between adjacent vertebralbodies is subject to collapse and/or misalignment due to the absence ofall or part of the intervertebral disc. In such situations, thephysician may insert one or more prosthetic spacers between the affectedvertebrae to maintain normal disc spacing and/or the normal amount oflordosis in the affected region.

Typically, a prosthetic implant is inserted between the adjacentvertebrae and may include pathways that permit bone growth between theadjacent vertebrae until they are fused together. However, there existsa possibility that conventional prosthetic implants may be dislodged andmoved from their desired implantation location due to movement by thepatient before sufficient bone growth has occurred.

Bone growth is a key factor in ensuring adequate retention of theimplant to the vertebra. Specifically, bone ingrowth within and aroundthe prosthetic implant promotes fusion between the adjacent vertebra,thereby strengthening the joint therebetween. However, conventionalimplants do not allow optimal space for bone ingrowth. In theseinstances, as the prosthetic implants do not mimic bone density of theadjacent vertebra, the body may reject the implant, and non-union (i.e.,no fusion) may occur.

Conventional prosthetic implants are typically constructed in a mannerthat inhibits bone ingrowth, particularly those that include no spacesor avenues for such bone growth to occur within and around theprosthetic implant. The lack of fusion may allow the implant to becomedislodged or moved from its desired location. Additionally, in theinstances where the prosthetic implant includes a lumen for the packingof ingrowth material, the material is often able to dislodge from thelumen, and in some instances, from the implant, thereby reducing thechances that adequate bone ingrowth occurs.

Therefore, a need exists for a prosthetic implant that can mimic thedensity of bone or adequately retain ingrowth material therein to allowfor optimal bone ingrowth and provide a solid fusion of the vertebralsegments.

SUMMARY

In accordance with an embodiment of the present disclosure, there isprovided an interbody spacer including a body portion defining alongitudinal axis. The body portion includes a distal end portion, aproximal end portion, opposed side surfaces that extend between thedistal and proximal end portions, and top and bottom surfaces configuredand adapted to engage vertebral bodies. The interbody spacer includesfirst orifices defined through the top surface. The first orificesinclude orifices having first and second cross-sectional configurationsand are arranged in rows extending along the longitudinal axis.

In embodiments, the second cross-sectional configuration may be largerthan the first cross-sectional configuration. The first orifices may bearranged in each row of the longitudinal rows in an alternating patternof orifices having first and second cross-sectional configurations.

In embodiments, the first orifices may include orifices with a thirdcross-sectional configuration, wherein the third cross-sectionalconfiguration is larger than the second cross-sectional configuration.The first orifices may be arranged in each row of the longitudinal rowsin a pattern, such that the cross-sectional configuration of eachorifice of the first orifices increases from the first cross-sectionalconfiguration to the third cross-sectional configuration. Alternatively,the first orifices may be arranged in a random pattern.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected from the group consisting ofarcuate, more than four sides, quadrilateral, triangle, and sinusoidal.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected from the group consisting ofoval, kidney, elliptical, circular, teardrop, semicircle, and ovoid.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected form the group consisting ofsquircle, square, rhombus, trapezoid, and rectangle.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected from the group consisting ofhexagon, octagon, heptagon, and pentagon.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected from the group consisting ofisosceles, equilateral, scalene, arrowhead with arcuate base, and right.

In embodiments, each orifice of the first orifices may include across-sectional configuration selected from the group consisting ofgreek cross and clover.

In embodiments, second orifices may be defined through the bottomsurface. One of the first orifices may include a cross-sectionalconfiguration different than that of one of the second orifices. One ofthe first orifices may be offset from one of the second orifices.

In embodiments, a respective orifice of the first and second orificesmay be in open communication, thereby defining a respective channelthrough the body portion. Each channel includes a cross-sectionalconfiguration that varies in a direction from the top surface to thebottom surface.

In embodiments, each channel may include a sinusoidal cross-sectionalconfiguration. Alternatively, each channel may include a cross-sectionalconfiguration including spherical, cylindrical, frusto conical,ellipsoidal, hyperboloid, or any combination thereof. Alternatively,each channel may include a cross-sectional configuration includinghelical grooves disposed on an inner wall surface thereof.

In embodiments, a respective orifice of the first orifices may be inopen communication with an orifice defined through one of the opposedside surfaces, thereby defining a respective channel through the bodyportion.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described hereinbelowwith reference to the drawings, wherein:

FIG. 1 is a rear, perspective view of an interbody spacer provided inaccordance with the present disclosure;

FIG. 2, is a side view of the interbody spacer of FIG. 1;

FIG. 3 is a top view of the interbody spacer of FIG. 1;

FIG. 4 is a top view of another embodiment of an interbody spacersimilar to the interbody spacer of FIG. 1;

FIG. 5 is a top view of yet another embodiment of an interbody spacersimilar to the interbody spacer of FIG. 1;

FIG. 6 is a top view of still another embodiment of an interbody spacersimilar to the interbody spacer of FIG. 1;

FIG. 7 is a top view of another embodiment of an interbody spacersimilar to the interbody spacer of FIG. 1, without a cavity extendingtherethrough;

FIG. 8 is a side, cross-sectional, view of the interbody spacer of FIG.7, taken along section-line 8-8 of FIG. 7;

FIG. 8A is a side, cross-sectional, view of an alternate embodiment ofthe interbody spacer of FIG. 7, taken along section-line 8-8 of FIG. 7;

FIG. 8B is a side, cross-sectional, view of an alternate embodiment ofthe interbody spacer of FIG. 8, taken along section-line 8-8 of FIG. 7;

FIG. 9 is an illustration of a family of cross-sectional shapes for anorifice defined through an interbody spacer in accordance with thepresent disclosure;

FIG. 10 is an illustration of another family of cross-sectional shapesfor an orifice defined through an interbody spacer in accordance withthe present disclosure;

FIG. 11 is an illustration of yet another family of cross-sectionalshapes for an orifice defined through an interbody spacer in accordancewith the present disclosure;

FIG. 12 is an illustration of still another family of cross-sectionalshapes for an orifice defined through an interbody spacer in accordancewith the present disclosure;

FIG. 13 is an illustration of another family of cross-sectional shapesfor an orifice defined through an interbody spacer in accordance withthe present disclosure;

FIG. 14 is an illustration still another family of cross-sectionalshapes for an orifice defined through an interbody spacer in accordancewith the present disclosure;

FIG. 15 is an illustration of yet another family of cross-sectionalshapes for an orifice defined through an interbody spacer in accordancewith the present disclosure;

FIG. 16 is a side, cross-sectional view, of a family shapes for achannel defined through an interbody spacer in accordance with thepresent disclosure;

FIG. 17 is a side, cross-sectional view, of another family of shapes fora channel defined through an interbody spacer in accordance with thepresent disclosure;

FIG. 18 is a side, cross-sectional view, of yet another family of shapesfor a channel defined through an interbody spacer in accordance with thepresent disclosure;

FIG. 19 is a side, cross-sectional view, of still another family ofshapes for a channel defined through an interbody spacer in accordancewith the present disclosure;

FIG. 20 is a side, cross-sectional view, of another family of shapes fora channel defined through an interbody spacer in accordance with thepresent disclosure;

FIG. 21 is a side, cross-sectional view, of still another family ofshapes for a channel defined through an interbody spacer in accordancewith the present disclosure;

FIG. 22 is a side, cross-sectional view, of yet another family of shapesfor a channel defined through an interbody spacer in accordance with thepresent disclosure; and

FIG. 23 is a side, cross-sectional view, of still another family ofshapes for a channel defined through an interbody spacer in accordancewith the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are now described in detail withreference to the drawings in which like reference numerals designateidentical or corresponding elements in each of the several views. Ascommonly known, the term “clinician” refers to a doctor, a nurse, or anyother care provider and may include support personnel. Additionally, theterm “proximal” refers to the portion of the device or component thereofthat is closer to the clinician and the term “distal” refers to theportion of the device or component thereof that is farther from theclinician. In addition, the term “cephalad” is known to indicate adirection toward a patient's head, whereas the term “caudal” indicates adirection toward the patient's feet. Further still, for the purposes ofthis application, the term “lateral” indicates a direction toward a sideof the body of the patient, i.e., away from the middle of the body ofthe patient. The term “posterior” indicates a direction toward thepatient's back, and the term “anterior” indicates a direction toward thepatient's front. Additionally, in the drawings and in the descriptionthat follows, terms such as front, rear, upper, lower, top, bottom, andsimilar directional terms are used simply for convenience of descriptionand are not intended to limit the disclosure. In the followingdescription, well-known functions or constructions are not described indetail to avoid obscuring the present disclosure in unnecessary detail.

Referring now to the drawings, FIGS. 1-3 illustrate an interbody spacerprovided in accordance with the present disclosure and generallyidentified by reference numeral 10. Interbody spacer 10 includes a bodyportion 12 having a substantially contoured first end surface 14 (FIG.2) at a distal or leading end 16 and a second end surface 18 oppositethereto at a proximal or trailing end 20, having a substantially planarconfiguration. Axis A-A (FIG. 3) is defined through a midpoint of firstand second end surfaces 14, 18, respectively. Body portion 12 extendsbetween first and second end surfaces 14, 18 to define respective topand bottom surfaces 22 and 24 (FIG. 2), respectively, as well as opposedside surfaces 26, 28 (FIG. 3). As best illustrated in FIG. 2, top andbottom surfaces 22, 24 include a generally convex or arcuate profile,each extending in a cephalad and caudal direction (or vice-versa),respectively. Although shown and described as the top surface 22 beingoriented in a cephalad direction and the bottom surface 24 beingoriented in a caudal direction, the interbody spacer 10 may bepositioned such that the top surface 22 is in a caudal orientation andthe bottom surface 24 is in a cephalad orientation. As can beappreciated, top and bottom surfaces 22 and 24 may include a concaveprofile, a planar profile, or any combination thereof. In embodiments,top surface 22 may include a different profile than that of bottomsurface 24. Additionally, it is contemplated that top and bottomsurfaces 22, 24 may approximate in a direction along axis A-A (orvice-versa), or may approximate in a direction from side surface 26towards side surface 28 (or vice-versa), or any combination thereof.

As best illustrated in FIG. 3, opposed side surfaces 26, 28 aresubstantially planar, although other configurations are alsocontemplated such as convex, concave, or the like. Opposed side surfaces26, 28 approximate towards each other at distal end 16 alonglongitudinal axis A-A in order to facilitate insertion within theintervertebral space and enhance the atraumatic character of bodyportion 12. In this manner, the intersection of top and bottom surfaces22, 24 with each of first and second end surfaces 14, 18 and opposedside surfaces 26, 28 may include a fillet or rounded configuration 30 toinhibit sharp edges from causing trauma to the surrounding tissue and/orvertebral bodies.

Referring again to FIG. 1, second end surface 18 includes an aperture 32defined therethrough and extending along longitudinal axis A-A. Aperture32 is configured for selective engagement with a suitable insertion tool(not shown), such as that described in U.S. Patent Application No.2012/0158062, filed Oct. 11, 2011, the entire contents of which arehereby incorporated by reference herein. In embodiments, aperture 32 maybe threaded or otherwise include various features capable of selectivelyretaining a suitable insertion tool (not shown) therein, such as akeyhole configuration, quarter-turn configuration, or the like.

Each of opposed side surfaces 26, 28 includes a corresponding depressionor recess 26 a, 28 a defined therein adjacent second end surface 18.Recesses 26 a, 28 a extend along longitudinal axis A-A and aresymmetrically disposed on each of opposed side surfaces 26, 28 to definea substantially I-shaped configuration to second end surface 18 atproximal end 20. In cooperation with aperture 32, the recesses 26 a, 28a are further configured to enable engagement with stabilizing jaws of asuitable insertion instrument (not shown) to facilitate the insertion ofinterbody spacer 10. As can be appreciated, interbody spacer 10 may notinclude recesses 26 a, 28 a, and rather, include planar side surfaces26, 28 that extend between first and second end surfaces 14, 18.

Body portion 12 includes a through-bore or cavity 34 defined through topand bottom surfaces 22, 24, respectively. Although shown as having agenerally oval configuration, it is contemplated that through-bore 34may include any suitable shape such as square, rectangular, circular, orthe like, or may include a configuration similar to that of the outerperimeter of body portion 12. It is contemplated that through-bore 34may receive allograft material, autograft material, calciumphosphate/bone marrow aspirate (BMA), autogenous material, syntheticmaterials comprised of a biocompatible osteoconductive, osteoinductive,or osteogeneic material such as VITOSS® Synthetic Cancellous Bone VoidFiller material, or any other suitable biological material known in theart. Through-bore 34 includes a cross-sectional area or surface areathat is greater than any orifice of the plurality of orifices orenlarged orifices detailed hereinbelow. In embodiments, through-bore 34includes a surface area that is equal to or greater than 25% of thesurface area of top surface 22 or bottom surface 24.

Top and bottom surfaces 22, 24 of body portion 12 are configured toengage respective endplates of adjacent vertebral bodies. In thismanner, each of top and bottom surfaces 22, 24 includes at least firstand second surface regions 22 a, 22 b and 24 a, 24 b, respectively,which have distinct surface characteristics. As best illustrated in FIG.2, first surface regions 22 a, 24 a are disposed distal to secondsurface regions 22 b, 24 b and include a surface characteristic that isdifferent than that of second surfaces 22 b, 24 b. In embodiments, firstsurface regions 22 a, 24 a may include a same or similar surfacecharacteristic to that of second surface regions 22 b, 24 b, or each offirst and second surface regions 22 a, 24 a and 22 b, 24 b may includethe same or different surface characteristics, or any combinationthereof.

First surface regions 22 a, 24 a each have a plurality of protrusions(i.e., teeth) or ridges 36 disposed thereof to aid in securing interbodyspacer 10 to each respective adjacent vertebral body and stabilityagainst fore and aft, oblique or side to side movement of interbodyspacer 10 within the intervertebral space. Specifically, protrusions 36frictionally engage endplates of adjacent vertebral bodies and inhibitmovement of the interbody spacer 10 with respect to the adjacentvertebral bodies. In embodiments, a plurality of longitudinal grooves 38(FIGS. 1 and 3) may be defined within protrusions 36, each of whichextends along longitudinal axis A-A. Each of second surface regions 22b, 24 b includes substantially pyramidal protrusions 40, where eachpyramidal protrusion 40 includes a plurality of protrusions or ridgesdisposed thereon to similarly aid in securing interbody spacer 10 toeach respective adjacent vertebral body. In particular, each pyramidalprotrusion 40 includes opposed first and second faces that face,respectively, distally and proximally. Further, each pyramidalprotrusion 40 has third and fourth faces that face, respectively,medially and laterally. For a detailed description of an interbodyspacer having exemplary surface characteristics, reference can be madeto U.S. Pat. No. 8,801,791 to Soo et al., filed Sep. 27, 2007, theentire contents of which are hereby incorporated by reference herein.

Interbody spacer 10 is constructed of a biocompatible material, such ascommercially pure titanium or titanium alloy and includes a porositycapable of promoting bone ingrowth and fusion with interbody spacer 10.In this manner, top and bottom surfaces 22, 24 and opposed side surfaces26, 28 have a surface roughness that can promote bone growth and fusionwith interbody spacer 10. The surface roughness may be in a range ofabout 0.10-50 μm, and preferably in a range of about 3-4 μm. As can beappreciated, top and bottom surfaces 22, 24 and opposed side surfaces26, 28 may include the same or different surface roughness's (i.e., thesurface roughness of top surface 22 may be different than the surfaceroughness of bottom surface 24), or top and bottom surfaces 22, 24 andopposed side surfaces 26, 28 may not include a surface roughness;rather, top and bottom surfaces 22, 24 and opposed side surfaces 26, 28may be smooth. In embodiments top and bottom surfaces 22, 24 and opposedside surfaces 26, 28 may include any combination of surface roughness orsmooth surface. Additionally, body portion 12 includes a plurality oforifices 44 and 46 defined through top and bottom surfaces 22, 24 andopposed side surfaces 26, 28, respectively, configured to promote boneingrowth. Although illustrated as having a generally circularcross-section, orifices 44 may include any suitable cross-section, aswill be described in further detail hereinbelow. Orifices 46 areillustrated as having a generally diamond shaped cross-section, however,it is contemplated that orifices 46 may include any suitablecross-section, as will be described in further detail hereinbelow. Thecross-sectional shapes of orifices 44, 46 mimic bone growth alongHaversian canals and lamellar structures of bone. The plurality oforifices 44, 46 reduces the density and stiffness of interbody spacer 10to enable the application of bone putty or the like (e.g.,bone-morphogenetic proteins, etc.) to interbody spacer 10 to promotebone ingrowth within interbody spacer 10 and fusion to adjacentvertebral bodies. Bone ingrowth and fusion strengthens interbody spacer10. In this manner, the likelihood that micromotion would occur would bereduced.

As best illustrated in FIG. 3, the plurality of orifices 44 are arrangedin evenly spaced longitudinal rows along longitudinal axis A-A. Theplurality of orifices 44 includes orifices with a first diameter 44 a,orifices with a second diameter 44 b, and orifices with a third diameter44 c. In one non-limiting embodiment, the first diameter 44 a is 30 μm,the second diameter 44 b is 150 μm, and the third diameter 44 c is 500μm, although other suitable diameters are also contemplated. As can beappreciated, each of the orifices 44 may include a cross-sectioncorresponding to any cross-sectional shape detailed herein. As such, thecross-sectional area of each of orifice 44 a, 44 b, and 44 c may be0.000707 μm², 0.0177 μm², and 0.196 μm², respectively. In this manner,the plurality of orifices 44 is defined through top and bottoms surfaces22, 24 and arranged in groups of three orifices, 44 a, 44 b, 44 c, thatdefine a respective pattern along axis A-A of body portion 12.

Referring to FIG. 4, another embodiment of an interbody spacer providedin accordance with the preset disclosure is illustrated and generallyidentified by reference numeral 110. Interbody spacer 110 issubstantially similar to interbody spacer 10, and therefore only thedifferences therebetween will be described in detail in the interest ofbrevity. The orifices of the plurality of orifices 144 include orificeswith a first diameter 144 a and orifices with a second, larger, diameter144 b. In one non-limiting embodiment, the diameter of the firstdiameter 144 a is 150 μm and the diameter of the second diameter 144 bis 500 μm, although other diameters are also contemplated. As can beappreciated, each of the orifices 144 may include a cross-sectioncorresponding to any cross-sectional shape detailed herein. As such, thecross-sectional area of each of orifice 144 a and 144 b may be 0.0177μm² and 0.196 μm², respectively. In this manner, a pair of rows oforifices 144 having the second, larger diameter 144 b is defined throughthe distal end 116 of top surface 122 and the bottom surfaces (notshown) and extending in a direction transverse to longitudinal axis A-A.A pair of rows of orifices 144 having the first diameter 144 a isdisposed proximal to the pair of rows of orifices 144 having the second,larger diameter 144 b and extends in a direction transverse tolongitudinal axis A-A. This pattern is repeated in a proximal (ordistal) direction along axis A-A.

With reference to FIG. 5, yet another embodiment of an interbody spacerprovided in accordance with the present disclosure is illustrated andgenerally identified by reference numeral 210. Interbody spacer 210 issubstantially similar to interbody spacer 10, and therefore only thedifferences therebetween will be described in detail in the interest ofbrevity. The plurality of orifices 244 includes orifices having a firstdiameter 244 a and orifices having a second, larger, diameter 244 b. Inone non-limiting embodiment, the first diameter 244 a is 150 μm and thesecond diameter 244 b is 500 μm, although other diameters are alsocontemplated. As can be appreciated, each of the orifices 244 mayinclude a cross-section corresponding to any cross-sectional shapedetailed herein. As such, the cross-sectional area of each of orifice244 a and 244 b may be 0.0177 μm² and 0.196 μm², respectively. In thismanner, the plurality of orifices 244 is defined through top and bottomsurfaces 222, 224 such that the diameter of the plurality of orifices244 alternates between orifices having the first diameter 244 a andorifices having the second, larger, diameter 244 b in a direction alonglongitudinal axis A-A. This pattern is offset in a direction transverseto longitudinal axis A-A such that an orifice of the plurality oforifices 244 having a first diameter 244 a is only adjacent an orificeof the plurality of orifices 244 having a second, larger, diameter 244b.

With reference to FIG. 6, still another embodiment of an interbodyspacer provided in accordance with the present disclosure is illustratedand generally identified by reference numeral 310. Interbody spacer 310is substantially similar to interbody spacer 10, and therefore only thedifferences therebetween will be described in detail in the interest ofbrevity. The plurality of orifices 344 includes orifices of variousdiameters. In one non-limiting embodiment, the diameter of each orificeof the plurality of orifices 344 may vary between 50 μm and 1000 μm. Ascan be appreciated, each of the orifices 344 may include a cross-sectioncorresponding to any cross-sectional shape detailed herein. As such, thecross-sectional area of each of orifice 344 may be 0.0707 μm² and 0.385μm². The plurality of orifices 344 is defined through top surface 322and the bottom surfaces (not shown) in a random manner such that thereare no defined rows, and the diameters of each orifice of the pluralityof orifices 344 vary.

Referring now to FIGS. 7 and 8, an alternate embodiment of an interbodyspacer provided in accordance with the present disclosure is illustratedand generally identified by reference numeral 410. Interbody spacer 410is substantially similar to interbody spacer 10, and therefore, only thedifferences therebetween will be described in detail in the interest ofbrevity. Interbody spacer 410 does not include a through-bore definedthrough top surface 422 and the bottom surfaces (not shown). Rather, asbest illustrated in FIG. 8, interbody spacer 410 includes a void 448defined within an interior portion of body 412. In this manner, void 448does not breach leading or trailing surface 414, 418, top or bottomsurface 422, 424, or the opposed side surfaces 426, 428 (FIG. 7). In onenon-limiting embodiment, aperture 432 extends through a proximal end ofvoid 448 such that aperture 432 is in open communication therewith.Although illustrated as having a generally circular cross-section, it iscontemplated that void 448 may include any suitable shape and/or volume,such as spheroid, ovoid, cuboid, rectanguloid, ellipsoid, or the like.In certain embodiments, void 448 may include an amorphous shape.Additionally, as best illustrated in FIG. 8A, it is contemplated thatvoid 448 may be isolated from the plurality of orifices defined throughtop surface 422 and the plurality of orifices 446 defined through theopposed side surfaces 426, 428 (FIG. 7), or only one or the other. It isfurther contemplated that void 448 may include one or more protrusions(not shown) extending towards an interior portion of void 448. As can beappreciated, the one or more protrusions may include any suitable shape,such as frusto conical, spheroid, ovoid, cuboid, rectanguloid, conical,ellipsoid, or the like. By varying the shape and or volume of void 448,the density and stiffness of interbody spacer 410 may be likewisevaried, thereby allowing a clinician to select an implant more closelytailored to the density of adjacent vertebral bodies. In embodiments,interbody spacer 448 may include a plurality of smaller voids 448defined in an interior portion of body 412.

Alternatively, as best illustrated in FIG. 8B, interbody spacer 410 mayinclude no through-bore or void. In this manner, aperture 432 is blind(i.e., terminates in a distal face in an interior portion of interbodyspacer 410). Additionally, the plurality of orifices 446 defined throughthe opposed side surfaces includes a diamond shaped cross-section 446 aon distal and proximal ends 416, 420 and a random array of orificeshaving a circular cross-section 446 b and varying diameters definedthrough the opposed side surfaces (not shown) at a medial portion ofbody 412. As can be appreciated, the plurality of orifices 446 having adiamond-shaped cross-section 446 a may be defined through the medialportion of the opposed side surfaces and the random array of circularorifices 446 b may be defined through distal and proximal ends 416, 420of the opposed side surfaces, or any combination thereof.

Referring now to FIGS. 9-15, the plurality of orifices 44, 46 mayinclude various cross-sectional shapes of differing families. Asillustrated in FIG. 9, orifices 44, 46 may include a cross-sectionalshape having varying curvature, designated as a first family 50.Cross-sectional shapes included in first family 50 include oval 50 a,kidney 50 b, elliptical 50 c, circular 50 d, teardrop 50 e, semicircle50 f, and ovoid 50 g. As can be appreciated, orifices 44, 46 from firstfamily 50 may include any cross-sectional shape having an arcuate,curvate, or otherwise amorphous shape not otherwise illustrated in FIG.9.

A second family 52 of cross-sectional shapes having more than four sidesis illustrated in FIG. 10. In this manner, the plurality of orifices 44,46 may include a cross-sectional shape of a hexagon 52 a, an octagon 52b, a heptagon 52 c, and a pentagon 52 d. As can be appreciated, anypolygon having more than four sides may be included in second family 52,such as nonagon, decagon, dodecagon, etc.

With reference to FIG. 11, a third family 54 of cross-sectional shapesfrom which the plurality of orifices 44, 46 may be defined isillustrated. Third family 54 includes quadrilaterals, such as a squarewith rounded edges 54 a (such as a squircle), square 54 b, rhombus 54 c,trapezoid 54 d, and rectangle 54 e. As can be appreciated, third family54 may include any quadrilateral, such as parallelogram, kite, isoscelestrapezoid, trapezium, etc.

A fourth family 56 of cross-sectional shapes from which the plurality oforifices 44, 46 may be defined is illustrated in FIG. 12. Fourth family56 includes triangles, such as isosceles 56 a, equilateral 56 b, scalene56 c, arrowhead with arcuate base 56 d, and right 56 e. As can beappreciated, fourth family 56 may include any type of triangle known inthe art.

FIG. 13 illustrates a fifth family 58 of cross-sectional shapes fromwhich the plurality of orifices 44, 46 may be defined. Fifth family 58includes a greek cross 58 a and clover 58 b, although other similarcross-sectional shapes are contemplated, like, cross, star, or the like.

As illustrated in FIG. 14, a sixth family 60 of cross-sectional shapesfrom which the plurality of orifices 44, 46 may be defined includessinusoidal shapes having various lengths, widths, and number of sides. Afirst sinusoidal shape 60 a includes a width that is larger than that ofa second sinusoidal shape 60 b. A third sinusoidal shape 60 c includespointed opposed ends. As can be appreciated, any suitable sinusoidalshape may be included in sixth family 60.

FIG. 15 illustrates a seventh family 62 of cross-sectional shapes fromwhich the plurality of orifices 44, 46 may be defined. Thecross-sectional shapes included in the seventh family 62 include ornatedesigns having various circular designs as illustrated in first design62 a or rectangular designs as illustrated in second design 62 b. Firstdesign 62 a includes upper and lower apertures 62 aa and 62 ab defininga generally oval shape. First design 62 a includes a plurality ofadditional bores 62 ac defined in an interior portion thereof. In thismanner, a plurality of circular features resembling wheels and spokesand/or pinwheels are defined. The plurality of bores 62 ac define acorresponding plurality of bridges or spokes 62 ad that separate each ofeach of the upper and lower apertures 62 aa, 62 ab, and plurality ofbores 62 ac.

Similarly, second design 62 b includes upper and lower apertures 62 baand 62 bb defining a generally rectangular shape. A plurality ofelongate, arcuate, bores 62 bc are defined in an interior portion ofsecond design 62 b, the plurality of elongate, arcuate, bores 62 bcdefining cooperating to define a generally triangular shape. Theplurality of elongate, arcuate, bores 62 bc define a correspondingplurality of bridges 62 bd that separate each of the upper and lowerapertures 62 ba, 62 bb and plurality of bores 62 bc.

As can be appreciated, any of the above described families may beinterchanged or randomly selected as the cross-sectional shape oforifices 44, 46 defined through upper and lower surfaces 22, 24 oropposed side surfaces 26, 28, respectively, of body portion 12. Inembodiments, the plurality of orifices 44 defined through top surface 22may utilize a different cross-sectional shape than that of the pluralityof orifices 44 defined through bottom surface 24. Similarly, theplurality of orifices 46 defined through side surface 26 may include adifferent cross-sectional shape than the plurality of orifices 46defined through opposite side surface 28. It is contemplated that anynumber of combinations of cross-sectional shapes may be employed.

Referring now to FIGS. 16-23, the plurality of orifices 44, 46 definedthrough top and bottom surfaces 22, 24 and opposed side surfaces 26, 28define a respective channel through body portion 12. FIGS. 16-23illustrate a variety of families of channels that may be defined throughbody portion 12. As best illustrated in FIG. 16, a first family ofchannels 64 having a generally arcuate profile is illustrated. The firstfamily of channels 64 includes a first channel 64 a having a generallyarcuate profile. First channel 64 a includes a pair of bowed or bulgingsidewalls and includes a constant width. A second channel 64 b includesa generally sinusoidal profile. A third channel 64 c includes a pair ofchannels 64 ca, 64 cb defining a generally X-shaped configuration. Inthis manner, channel 64 ca of the pair of channels is bowed in a firstdirection and channel 64 cb of the pair of channels bows in an oppositedirection, such that channels 64 ca, 64 cb intersect (i.e., channels 64ca and 64 cb are in open communication). A fourth channel 64 d includesa generally hourglass profile. A fifth channel 64 e includes anelliptical profile. As can be appreciated, first family of channels 64may include any suitable profile having arcuate sidewalls.

FIG. 17 illustrates a second family of channels 66 having generallyplanar sidewalls. First channel 66 a includes planar sidewalls extendingin a diagonal direction such that the openings of an orifice of theplurality of orifices 44, 46 on the top and bottom surfaces 22, 24,respectively, are offset in relation to one another. A second channel 66b includes a generally arrowhead or rotated chevron type profile (i.e.,upper and lower portions extending diagonally toward one another in amedial portion of body portion 12 to define a point). A third channel 66c includes a generally hourglass profile having planar sidewalls. Afourth channel 66 d includes a generally inverted hourglass profile(i.e., the width of fourth channel 66 d increases at a middle portionthereof).

A third family of channels 68 is illustrated in FIG. 18. Each channel ofthe third family of channels 68 is mirrored about axis B-B defined at amedial portion of body 12. A first channel 68 a is defined through topsurface 22 and includes a first cylinder 68 aa having a first diameterextending towards bottom surface 24. First cylinder 68 aa transitions toa second cylinder 68 ab and includes a second, larger, diameter than thediameter of first cylinder 68 aa. A second channel 68 b is essentiallyan inverse of first channel 68 a. In particular, a first cylinder 68 bahaving a first diameter intersects top surface 22 and extends towardsbottom surface 24. First cylinder 68 ba transitions to a second cylinder68 bb and includes a second, smaller, diameter than the diameter offirst cylinder 68 ba.

Referring now to FIG. 19, a fourth family of channels 70 is illustrated.A first channel 70 a is defined through top surface 22 of body portion12 and includes a generally arcuate shape such that first channel 70 acurves towards, and extends through, one of opposed side surfaces 26,28. A second channel 70 b is defined through bottom surface 24 of bodyportion 12 and includes a generally arcuate shape such that secondchannel 70 b curves towards, and extends through, an opposite one ofopposed side surfaces 26, 28 than that of first channel 70 a.

FIG. 20 illustrates a fifth family of channels 72 including similarprofile to that of the fourth family of channels 70. In this manner, afirst channel 72 a includes a tighter radius of curvature than that of asecond, opposed channel 72 b. As can be appreciated, second channel 72 bmay have a tighter radius than that of first channel 72 a.

A sixth family of channels is illustrated in FIG. 21 and is generallyidentified by reference numeral 74. Each channel of the third family ofchannels 74 is mirrored about axis B-B defined at a medial portion ofbody 12. A first channel 74 a includes a frusto conical profile 74 aadefined through top surface 22 of body portion 12 extending towardsbottom surface 24. Frusto conical profile 74 aa includes a generallyinverted orientation (i.e., the diameter decreases in a direction fromtop surface 22 towards bottom surface 24). Frusto conical profile 74 aatransitions to a cylindrical profile 74 ab at a medial portion of bodyportion 12 having a larger diameter than that of the portion of frustoconical profile 74 aa that intersect cylindrical profile 74 ab.

A second channel 74 b includes a substantially similar profile to thatof first channel 74 a except that the frusto conical profile 74 ba isinverted with respect to frusto conical profiles 74 aa of first channel74 a.

Third channel 74 c includes first portion 74 ca having a generallyhourglass configuration that intersects top surface 22 of body portion12 and extends towards bottom surface 24. First portion 74 catransitions to a second portion 74 cb having a generally cylindricalconfiguration at a medial portion of body portion 12.

A fourth channel 74 d includes a first portion 74 da having a generallyspherical configuration. First portion 74 da is defined through topsurface 22 of body portion 12 and extends towards bottom surface 24.First portion 74 da transitions to a second portion 74 db having agenerally cylindrical configuration at a medial portion of body portion12. Second portion 74 db includes a diameter less than the diameter offirst portion 74 da.

FIG. 22 illustrates a seventh family of channels generally identified byreference numeral 76. Each channel of the third family of channels 76 ismirrored about axis B-B defined at a medial portion of body 12. A firstchannel 76 a includes a first and second spherical portion 76 aa and 76ab respectively, disposed in a generally stacked configuration such thatfirst spherical portion extends through upper surface 22 of body 12.Each of first and second spherical portions 76 aa and 76 ab include agenerally similar diameter, although other configurations are alsocontemplated.

A second channel 76 b includes a first portion 76 ba defined through topsurface 22 of body portion 12 and extending towards bottom surface 24.First portion 76 ba includes a generally cylindrical configuration andtransitions to a second portion 76 bb having a generally sphericalconfiguration at a medial portion of body portion 12.

Third channel 76 c includes a first portion 76 ca having a generallyinverted frusto conical configuration (i.e., the diameter of firstportion decreases in a direction from top surface 22 towards bottomsurface 24). First portion 76 ca is defined through top surface 22 ofbody portion 12 and extends towards bottom surface 24. First portion 76ca transitions to a second portion 76 cb having a generally ellipsoidconfiguration at a medial portion of body portion 12, although it iscontemplated that second portion 76 cb may include a generally sphericalconfiguration similar to that of second portion 76 bb of second channel76 b.

Fourth channel 76 d is similar to that of third channel 76 c except thatthe first portions 76 da includes a frusto conical configuration that isinverted relative to first portion 76 ca of third channel 76 c. Secondportion 76 db includes a generally spherical configuration.

A fifth channel 76 e includes a first portion 76 ea having a generallyhourglass configuration. First portion 76 ea is defined through topsurface 22 of body portion 12 and extends towards bottom surface 24.First portion 76 ea transitions to a second portion 76 eb having agenerally spherical configuration at a medial portion of body portion12.

FIG. 23 illustrates an eighth channel 78 defined through top and bottomsurfaces 22, 24 of body portion 12. Eighth channel 78 includes agenerally cylindrical profile including helical grooves 78 b defined onan inner sidewall 78 a thereof.

Although each orifice and channel has been hereinabove described asbeing defined through top and bottom surfaces 22, 24 of body 12, as canbe appreciated, the orifices and channels may be defined through opposedside surfaces 26, 28.

As can be appreciated, manufacturing interbody spacers 10, 110, 210,310, and 410 using standard machining methods (e.g., lathe, mill, EDM,etc.) could be difficult. In view of this, it is contemplated that inaddition to manufacturing interbody spacers 10, 110, 210, 310, and 410using the aforementioned conventional means, interbody spacers 10, 110,210, 310, and 410 may be manufactured by means of additive manufacturingmethods (e.g., SDM, SLPP, DMLS (i.e., EOS), SLS, SLM, SHS, EBM, VATphotopolymerisation, material jetting, binder jetting, or the like). Inone non-limiting embodiment, interbody spacers 10, 110, 210, 310, and410 may be manufactured using Selective Laser Powder Processing (SLPP).SLPP utilizes powdered metal and a laser which sinters or cures themetal in a selective fashion according to the design intent in thinlayers. In embodiments, the layers have a thickness of about 250 μm.Interbody spacers 10, 110, 210, 310, and 410 are built layer by layer toallow for more design options and features that would be difficult to bemachined using conventional methods. Specifically, a first layer ofpowder is applied to a specialized build plate, at which point the lasercures portions of the powder according to the design intent. At thispoint, a second layer is applied to the build plate and the laser isagain used to cure selective portions of this second layer. This processis repeated until interbody spacers 10, 110, 210, 310, and 410 are fullyformed. Once interbody spacers 10, 110, 210, 310, and 410 are fullyformed, uncured powder is removed using compressed air or other similarmeans. Next, post machining is performed on interbody spacers 10, 110,210, 310, and 410 to remove any burrs or similar imperfections embeddedwithin interbody spacers 10, 110, 210, 310, and 410 during the additivemanufacturing process. In embodiments, the burrs are removed by means ofbuffer wheels, clippers, files, or the like. Once de-burred, interbodyspacers 10, 110, 210, 310, and 410 are heat treated, and thereafter,media blasted using aluminum oxide. Thereafter, interbody spacers 10,110, 210, 310, and 410 are immersed in a hydrofluoric bath to strip thealuminum oxide therefrom. Finally, interbody spacers 10, 110, 210, 310,and 410 are inspected by quality control personnel (or using automatedmeans), cleaned via ultrasonic cleaning, dried, and packaged. It iscontemplated that the design of interbody spacers 10, 110, 210, 310, and410 may be customized for each specific patient using SLPP. For adetailed description of exemplary manufacturing methods, reference maybe made to U.S. Pat. No. 8,590,157, issued on Nov. 26, 2013 to Kruth etal., the entire contents of which are hereby incorporated by referenceherein.

Interbody spacers 10, 110, 210, 310, and 410 may be constructed fromcommercially pure titanium, titanium alloy, cobalt-chrome, ceramic,Polyetheretherketone (PEEK), or any other suitable biocompatiblematerial. In embodiments, interbody spacers 10, 110, 210, 310, and 410may be manufactured using a three-dimensional printer utilizing abiocompatible polymer.

With reference to FIGS. 1-8B, in use, an intervertebral space is firstprepared, e.g., damaged or diseased tissue is removed. As theconstruction of interbody spacer 10 is similar to that of interbodyspacers 110, 210, 310, and 410, only the method of use of interbodyspacer 10 will be described in detail for purposes of brevity. Anappropriately sized interbody spacer 10 is selected based on thepatient's spinal characteristics and the desired amount of lordosis.Next, the interior space of through-bore 34 of body portion 12 may bepacked with bone in-growth material, drugs, or other suitable materialsor compounds. Examples of such materials are allograft material, orsynthetic materials comprised of a biocompatible, osteoconductive,osteoinductive, or osteogeneic material such as VITOSS® SyntheticCancellous Bone Void Filler material. Next, a suitable insertioninstrument (not shown) is threaded into aperture 32 of body portion 12until interbody spacer 10 is securely affixed to the insertioninstrument. At this point, interbody spacer 10 is advanced within anincision within the patient, and thereafter, the previously preparedinverterterbal space of the patient's spine. Once interbody spacer 10 isplaced within the intervertebral space such that interbody spacer 10rests on the distal apophyseal ring of the vertebral body, the tool (notshown) is released from aperture 32, and thereafter, the incision withinthe patient. By residing on the apophyseal ring, interbody spacer 10 isless likely to experience subsidence into the end plates which willfacilitate fusion between the intervertebral plates.

This process may be repeated as many times as the procedure requires,whether it be for the same interbody spacer 10 or for a plurality ofinterbody spacers 10 as required by the procedure being performed.

It is envisioned that the manufacturing processes and orifice designsdetailed above may be utilized to form various other medical devicesknown in the art. In this manner, the additive manufacturing processdetailed above may be employed to form corpectomy devices, fixed spinalimplants, expandable spinal implants, bone screws, cervical implants,and the like. Similarly, the orifice designs detailed above may beformed in any of the beforementioned medical devices that would benefitfrom an increased ability to fuse with bone. Examples of such devicesmay be found in the following commonly owned references: U.S. Pat. No.8,585,761 to Theofilos, U.S. Pat. No. 8,673,011 to Theofilos et al.,U.S. patent application Ser. No. 14/936,911 to Sutterlin et al., U.S.Pat. No. 8,801,791 to Soo et al., U.S. Pat. No. 8,439,977 to Kostuik etal., U.S. Patent Application Publication No. 2010/0100131 toWallenstein, U.S. Patent Application Publication No. 2012/0179261 toSoo, U.S. Pat. No. 8,449,585 to Wallenstein et al., U.S. Pat. No.8,814,919 to Barrus et al., U.S. Pat. No. 5,733,286 to Errico et al.,and U.S. Patent Application Publication No. 2013/0046345 to Jones et al.

It will be understood that various modifications may be made to theembodiments of the presently disclosed interbody spacer. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of embodiments. Those skilled in the art will envisionother modifications within the scope and spirit of the presentdisclosure.

What is claimed is:
 1. An interbody spacer comprising: a body portion defining a longitudinal axis, the body portion including a distal end portion, a proximal end portion, opposed side surfaces that extend between the distal and proximal end portions, and top and bottom surfaces configured and adapted to engage vertebral bodies; and first orifices defined through the top surface; second orifices defined through the bottom surface, wherein a respective orifice of the first and second orifices is in open communication thereby defining a channel therebetween, wherein the channel defines a plurality of cross-sections, a center cross-section of the plurality of cross-sections defining a cross-sectional area that is greater than cross-sections disposed adjacent the top surface and the bottom surface.
 2. The interbody spacer of claim 1, wherein the channel defines a plurality of cylinders, a center cylinder having a cross-sectional area greater than a cross-sectional area of adjacent cylinders.
 3. The interbody spacer of claim 1, wherein the channel defines a plurality of spheres, a center sphere having a cross-sectional area different than a cross-sectional area of adjacent spheres.
 4. The interbody spacer of claim 1, wherein a center portion of the channel defines a cylindrical profile and upper and lower portions of the channel define a frusto-conical profile.
 5. The interbody spacer of claim 4, wherein a diameter of each frusto-conical profile decreases in a direction towards the center of the channel such that the diameter of each frusto-conical profile at a center portion of the channel is less than a diameter of the cylindrical profile.
 6. The interbody spacer of claim 1, wherein a center portion of the channel defines a cylindrical profile and the upper and lower portions of the channel define an hourglass profile.
 7. The interbody spacer of claim 1, wherein a center portion of the channel defines a spherical profile and the upper and lower portions of the channel define an hourglass profile.
 8. The interbody spacer of claim 1, wherein the body portion is formed from powder processed using Selective Laser Powder Processing. 